Sighting system for a firearm-carried grenade launcher

ABSTRACT

A sighting system for a grenade launcher carried by a shouldersupported firearm includes a front sight mounted on the launcher for elevational adjustment by means of a track disposed at a predetermined angle relative to the vertical axis thereof to compensate for grenade drift as the front sight is moved along the track for range adjustment. The rear sight is adjustable for windage correction and is pivotally mounted on the firearm so as to be swung thereagainst, out of the way, when not in use.

United States Patent [72] Inventor Stanley D. Silsby Granby, Mass. [21]Appl. No, 834,117 [22] Filed June 17, 11969 [45] Patented Sept. 14, 1971[73] Assignee The United States of America as represented by theSecretary of the Army [54] SIGHTING SYSTEM FOR A FIREARM-CARRIED GRENADELAUNCHER 5 Claims, 11 Drawing Figs.

[52] US. Cl 42/1 S,

' 33/47 [51] lnt.Cl F4lc [50] Field of Search 42/1 F, 1 S; 33/47, 48, 53

[56] References Cited UNITED STATES PATENTS 1,340,453 5/1920 Lera 42/1 F2,068,821 1/1937 Savani 42/1 1- 2,335,881 12/1943 Persinger... 33/473,165,836 1/1965 Magardo... 33/47 3,435,549 4/1969 Kermode.... 42/1 FPrimary Examiner-Benjamin A. Borchelt Assistant Examiner-C. T. JordanAnomeysHarry M. Saragovitz, Edward J. Kelly, Herbert Berl and Albert E.Arnold, Jr.

ABSTRACT: A sighting system for a grenade launcher carried by ashoulder-supported firearm includes a front 'sight" mounted on thelauncher for elevational adjustment by means of a track disposed at apredetermined angle relative to the vertical axis thereof to compensatefor grenade drift as the front sight is moved along the track for rangeadjustment. The rear sight is adjustable for windage correction and ispivotally mounted on the firearm so as to be swung thereagainst, out ofthe way, when not in use.

PATENTED SEPI 41971 SHfEI 1 [IF 2 INVENTOR Elunlgy I! 5 flag ATTORNEYSPATENTEU SEP] 4 |97| SHEET 2 OF 2 SIGHTING SYSTEM FOR A FIREARM-CARRIEDGRENADE LAUNCHER The invention described herein may be manufactured,used, and licensed by or for the US. Government for governmentalpurposes without the payment to me of any royalty thereon.

BACKGROUND OF THE INVENTION This invention pertains to sighting devicesfor firearms and provides for grenade launchers carried byshoulder-supported firearms, a separate sighting system that includes afront sight mounted on the grenade launcher and adapted for elevationaladjustment and automatic compensation for lateral drift of the grenadein flight, and a rear sight pivotally mounted on the basic firearm sothat it can be swung out of the way when not in use and which isadjustable for windage correction.

Included in the arsenal of modern firearms are shouldersupportedfirearms which carry an auxiliary firearm for launching grenades tothereby increase the firepower available to the troops. These grenadelaunchers discharge the grenade at a low velocity and high trajectoryand therefore the sight system for the launcher must be entirelydifferent from that of the basic firearm. Considerable difficulty hasbeen encountered in providing for these launchers a suitable sightingsystem which can be used comfortably by the shooter. Because of thenecessary elevation required of the firearm to lob the grenade todistant targets, and because of the proximity of the rear sights to theeye of the shooter with conventional sighting systems, considerable andawkward adjustment of the head of the shooter is required for thefull-range adjustments and sometimes the firearm cannot even besupported on the shoulder when sighting at a long-range target.

SUMMARY OF THE INVENTION It is a principal object of this invention toprovide for shoulder-supported firearms having an auxiliary grenadelauncher mounted thereon a separate sighting system for the launcherdesigned so that the firearm can be elevated for the different rangeadjustments of the launcher from the shoulder of the shooter, and with aminimum of a change required in the head position of the shooter, whensighting on the target.

it is another object of this invention to provide such a sighting systemin which the rear sight is adjustable for windage correction and thefront sight is adjustable for elevation and is also adapted toautomatically compensate for lateral drift of the grenade caused by theinduced spin therein, at the different range adjustments.

It is a further object of this invention to provide such a sightingsystem wherein the rear sight is mounted on the basic,shoulder-supported firearm for pivotal displacement against the firearmwhen not in use and the front sight is mounted on the auxiliary grenadelauncher.

It is a still further object of this invention to provide such asighting system which is simple and rugged in construction so as to beadaptable for rough usage and which adds a minimum amount of bulk to thefirearms.

Further objects and advantages of the invention will be apparent fromthe following specification and the accompanying drawings which are forthe purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of ashoulder-supported firearm with a grenade launcher mounted thereon;

FIG. 2 is an enlarged, fragmentary view of the firearm where thesighting system of this invention is mounted thereto;

FIG. 3 is a view taken along line 3-3 of FIG. 2;

FIG. 4 is a view similar to FIG. 3 but showing the rear sight pressed into release it so it can be swung to the folded position;

FIG. 5 is a view taken along line 5-5 of FIG. 2;

FIG. 6 is a view taken along line 6-6 of FIG. 2;

FIG. 7 is a view taken along 7-7 of FIG. 6;

FIG. 8 is a view taken along line 88 of FIG. 2;

FIG. 9 is a schematic view showing, exaggerated, the relationshipbetween the sight line and bore axis of the launcher in the horizontalplane with the drift of the grenade being compensated for at the 75-yardadjustment;

FIG. 9a is a view similar to FIG. 9 but shows the relationship betweenthe sight line and bore axis when the sighting system is adjusted forthe 250-yard range; and

FIG. 9b is a view similar to FIGS. 9 and 9a but shows the relationshipbetween the sight line and bore axis when the sighting system isadjusted for the 375-yard range.

DESCRIPTION OF A PREFERRED EMBODIMENT Shown in the figures is a rifle 12with a grenade launcher 14 mounted underneath barrel 16 thereof.Launcher 14 includes a housing 18 having a T-slot 22 formed in the leftside so as to slant upwardly and outwardly at a predetermined anglerelative to the vertical axis of the launcher, for a purpose to beexplained hereinafter. T-slot 22 slidingly mounts a metering bar 24which is slidable therein for bore-sighting adjustment and is secured inthe adjusted position by screw 26. Extending along the length ofmetering bar 24 is a T-shaped channel 28 which opens outwardly along theleft side thereof and slidingly mounted in such channel is a front sight30 of blade type. The upward and downward movement of front sight 30 inchannel 28 is limited by roll pins 32 which extend through channel 28,as shown in FIG. 2.

Provided along the rear face of metering bar 24 so as to be seen by theshooter, as shown in FIG. 8, is a scale 33 which has been calibrated inincrements of 25 yards of range adjustment extending from 75 to 375yards. A reference line 34 on the rear face of front sight 30 isalignable with the calibrations of scale 33 to correctly index the frontsight at the desired range setting. Front sight 30 is releasably held inthe selected position through the cooperation of a spring-pressed ball36 in the front sight with spherical indents 38 formed in inner surface44 of channel 28, as shown in FIG. 2. Because of the angle of T-slot 22relative to the vertical axis of launcher l4, metering bar 24 issimilarly inclined and this angle is determined by the predeterminedlateral drift of the grenade at the different range calibrations onscale 33.

Rifle 12 is provided with a handle 42 located along the top thereofrearwardly of launcher 14, which handle includes an opening 45 forreceiving the fingers ofa hand for carrying the firearms. Opening 45 isterminated at the rear end by a planar wall 46 which is normal to thelongitudinal axis of rifle 12. Extending forwardly from wall 46 is a lug48 which is hexagonal in cross section as shown in FIG. 4 and whichpivotally supports rear sight 50. Such rear sight 50 includes a collar52 which receives lug 48 so as to permit radial displacement rela' tivethereto, and a shaft 54 that extends radially therefrom. Shaft 54 isbored axially at 56 into collar 52 and installed in such bore is aplunger 58 and a spring 60 for biasing the plunger against lug 48. Theouter end of bore 56 is threaded at 62 to threadingly mount an aperture64 having an eyepiece 66 with a rod 68 extending therefrom. Rod 68includes a threaded portion 70 that engages threaded section of bore 56,and a calibrated section 72 disposed between the threaded section andeyepiece 66. Installation of aperture 64 in bore 56 tensions spring 60to bias plunger 58 against side 76 of lug 48, which is formed normal tothe axis of rear sight 50 when located in its extended operativeposition, as shown in FIG. 3. Lug 48 is also provided with two sides 78which are disposed opposite side 76 and symmetrical thereto and suchsides contact mating sides 80 formed in collar 52, as shown in FIGS. 3and 4, when rear sight 50 is in its extended operative position, toreleasably hold the rear sight therein. To swing rear sight 50 down toits folded inoperative position, aperture 64 is pressed inwardly againstthe bias of spring 60 as shown in FIG. 4 for disengaging sides 78 on lug48 from sides 80 in ring 52, to where the rear sight is free for pivotaldisplacement. When rear sight 50 is in its inoperative position, asshown in phantom in FIG. 3, it is held therein by the spring-pressedcontact of plunger 58 with side 82 of lug 48. Rear sight 50 is pivotedto its operative position by reversing the above steps and when in theoperative position it is positioned for operational cooperation withfront sight 30, as shown in FIG. 8.

When rear sight 50 is in its extended operative position, the sightingsystem 84 of this invention is used for aiming launcher 14 at target 86by moving front sight 30 along meter bar 24 to where reference line 34is in alignment with the calibration on scale 33 which corresponds tothe estimated distance of the target. As front sight 30 is moved upmeter bar 24, to decrease the target range adjustment by decreasing theangle of sight line xx relative to bore axis y-y of launcher 14, it isalso moved outwardly according to the angle of the bar relative to thevertical axis of launcher 14 to compensate for the predetermined lateraldrift of the projectile at the selected range setting, as shown in FIGS.9, 9a and 9b. Moreover, it is obvious that by having the rear sightfixed to rifle 12 for elevational sighting and having the front sightadjustable, the adjustment of sighting system 84 for elevation requiresless adjustment of the eye of the shooter to the various range settingsthan when the front sight is fixed and the rear sight is adjustable asin conventional sight systems.

lwish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

I claim:

1. A sighting system for a firearm comprising a shouldersupported rifleand a launcher for grenades mounted thereon including a front sight, achanneled metering bar mounting said front sight on said launcher forsliding elevational adjustments, a rear sight including an aperture,means for mounting said rear sight for windage adjustment, and a lug onsaid rifle cooperating with said rear sight for releasably securing saidrear sight in an extended operative position and a folded inoperativeposition.

2. The sighting system as defined in claim 1 wherein said metering baris provided with a scale calibrated according to increments of rangedistances and said front sight is provided with an index line alignablewith said calibrations. and including a T-slot formed in said firearmfor slidingly mounting said metering bar for bore sight adjustment andto incline said metering bar relative to the vertical axis of thefirearm so as to position said front sight for automaticallycompensating said front sight for lateral drift of the grenades at thedifferent range calibrations on said metering bar.

3. The sighting system as defined in claim 2 wherein said metering baris provided with a channel ofT-configuration for slidingly mounting saidfront sight, and including a springpressed ball in said front sight, andspherical indents in said channel cooperating with said ball forreleasably securing said front sight at the different calibrations onsaid metering bar.

4. The sighting system as defined in claim 2 wherein said front sight ismounted on said launcher and said rear sight is mounted on said rifle.

5. The sighting system as defined in claim 2 wherein said lug islongitudinally disposed on the rifle and is of hexagonal configurationin cross section, and including a collar portion of said rear sightencircling said lug to provide pivotal support for said rear sight andpermit radial movement thereof respective to said lug, a spring-biasedplunger pressed against said lug, a one side of said lug arranged forcontact by said plunger when said rear sight is in the extendedoperative position, a pair of sides of said lug disposed opposite saidone side so as to be pressed against a mating pair of surfaces in saidcollar by the bias of said plunger to releasably hold said rear sight inthe extended operative position and so as to be free of said pair ofsurfaces when said rear sight is pressed inwardly against the bias ofsaid plunger to release said rear sight for pivotal displacement to afolded inoperative position, and a fourth side on said lug contactableby said plunger when said rear sight is in the inoperative position toreleasably hold the sight therein.

1. A sighting system for a firearm comprising a shouldersupported rifleand a launcher for grenades mounted thereon including a front sight, achanneled metering bar mounting said front sight on said launcher forsliding elevational adjustments, a rear sight including an aperture,means for mounting said rear sight for windage adjustment, and a lug onsaid rifle cooperating with said rear sight for releasably securing saidrear sight in an extended operative position and a folded inoperativeposition.
 2. The sighting system as defined in claim 1 wherein saidmetering bar is provided with a scale calibrated according to incrementsof range distances and said front sight is provided with an index linealignable with said calibrations, and including a T-slot formed in saidfirearm for slidingly mounting said metering bar for bore sightadjustment and to incline said metering bar relative to the verticalaxis of the firearm so as to position said front sight for automaticallycompensating said front sight for lateral drift of the grenades at thedifferent range calibrations on saId metering bar.
 3. The sightingsystem as defined in claim 2 wherein said metering bar is provided witha channel of T-configuration for slidingly mounting said front sight,and including a spring-pressed ball in said front sight, and sphericalindents in said channel cooperating with said ball for releasablysecuring said front sight at the different calibrations on said meteringbar.
 4. The sighting system as defined in claim 2 wherein said frontsight is mounted on said launcher and said rear sight is mounted on saidrifle.
 5. The sighting system as defined in claim 2 wherein said lug islongitudinally disposed on the rifle and is of hexagonal configurationin cross section, and including a collar portion of said rear sightencircling said lug to provide pivotal support for said rear sight andpermit radial movement thereof respective to said lug, a spring-biasedplunger pressed against said lug, a one side of said lug arranged forcontact by said plunger when said rear sight is in the extendedoperative position, a pair of sides of said lug disposed opposite saidone side so as to be pressed against a mating pair of surfaces in saidcollar by the bias of said plunger to releasably hold said rear sight inthe extended operative position and so as to be free of said pair ofsurfaces when said rear sight is pressed inwardly against the bias ofsaid plunger to release said rear sight for pivotal displacement to afolded inoperative position, and a fourth side on said lug contactableby said plunger when said rear sight is in the inoperative position toreleasably hold the sight therein.